Overhead distribution electrical networks comprise a large number of poles. When these poles reach the end of their life, they must be replaced. The transfer of a three-phase line (or having a different number of phases) from an old pole to a new pole requires to raise and move the medium voltage conductors. To avoid electrical supply interruption, this transfer is generally made while the line is live, which requires specific safety procedures.
The transfer of an energized overhead electrical line can be carried out from a distance using one or several sticks. The transfer of the conductors is carried out by installing a temporary support (two supports are sometimes necessary) onto which the conductors are transferred one by one. The existing crossarm on the pole to be replaced is then dismantled, and a crossarm is installed on the new pole. The conductors are then again transferred one by one on the new crossarm, and the temporary support is dismantled. The procedure is thus limited to the displacement of a single conductor at once and requires the installation of one or two supports to temporarily support the conductors.
In locations unreachable to a bucket truck, the handling of the live electrical conductors must be manually carried out from a distance with insulating sticks. This type of work is strenuous on the physical level and takes a long time. In the case where the line is located in a location reachable to a bucket truck, the handling of the conductors can be carried out using the fly jib of the truck. In both cases, temporary supports must be installed.
When the location is reachable, there are certain devices allowing simultaneous raising and displacement of the conductors of a three-phase line. Examples of such devices are shown in U.S. Pat. No. 4,466,506 (Dolenti) and U.S. Pat. No. 5,076,449 (Clutter). In these devices, a temporary crossarm is carried by an arm sliding in a support mounted to the bucket of a bucket truck. The crossarm has brackets for receiving the conductors to be moved. The brackets are actuated through a stick by an operator stationed in the bucket, under the conductors which are possibly live. The bucket truck must have a strong lift capacity and is generally not usable in backyards. Certain safety problems may happen in case of emergency. For example, the bucket cannot be easily and quickly lowered back to ground because the conductors are captured in the conductor holders. Furthermore, the mechanical load produced by the lifting of the conductors may exceed the lift capacity of the bucket truck. U.S. Pat. No. 5,538,207 (O'Connell et al.) shows a similar device but directly mounted at the end of the boom of a truck.